1. Field of the Invention
The present invention generally relates to elevating mechanisms, and particularly, to an elevating mechanism for a flat-panel display monitor and a pneumatic cylinder for adjusting the height of the elevating mechanism.
2. Discussion of the Related Art
Display devices of the computers come in a variety of sizes, shapes, and weights. Flat-panel display monitors, such as liquid crystal display (LCD) monitors, are widely used because of their thin bodies and light weight.
LCD monitors can also be versatile. Generally, the height of the flat-panel display monitor can be adjusted via an elevating mechanism.
Referring to FIG. 7, a typical elevating mechanism 100 includes a support member 10, a mounting bracket 20, and a coil spring 30. The support member 10 includes an elongated main portion (not labeled), and two side portions (not labeled) extending from opposite sides of the elongated main portion. The main portion and the side portions cooperatively define a receiving groove 11 for mounting the mounting bracket 20. Two guide rails 12 are formed on opposite inner surfaces of the side portions. The support member 10 further defines two fixing holes 13 adjacent to top ends of the side portions.
The mounting bracket 20 includes a middle portion (not labeled), two sliding portions (not labeled) extending from opposite sides of the middle portion, and a connecting portion 21 connected to an end of the middle portion. The middle portion defines two threaded holes 22 in another end of the middle portion opposite to the connecting portion 21. The two sliding portions are configured to engage in the guide rails 12 of the support member 10 so that the mounting bracket 20 is slidable in the receiving groove 11.
The coil spring 30 includes a first end coiled to a shaft 31 and a second end opposite to the first end defining two through holes 32. The shaft 31 defines two fixing holes 311 in opposite ends of the shaft 31. The shaft 31 is fixed to the support member 10 by using screws 33 to pass through the fixing holes 311 and screwed into the two corresponding fixing holes 13 of the support member 10. The second end of the coil spring 30 is fixed to the mounting bracket 20 by using screws 36 to pass through the through holes 32 and screwed into the corresponding threaded holes 22.
The connecting portion 21 of the mounting bracket 20 supports a flat-panel display (not shown). To lower the height of the flat-panel display, an external force is applied to the flat-panel display causing the mounting bracket 20 to slide downwards relative to the support member 10. When the mounting bracket 20 slides to a desired position, the external force is released. The mounting bracket 20 with the flat-panel display remains in the desired position by an elastic force from the coil spring 30 and a friction force created between the mounting bracket 20 and the support member 10. To raise the height of the flat-panel display, another external force is applied to the flat-panel display for lifting the mounting bracket 20 to slide upwards relative to the support member 10 to another desired position.
However, the support member 10 and the mounting bracket 20 are generally heavy. In addition, the conventional elevating mechanism 100 has a relatively short usage life because the coil spring 30 damages easily when it is frequently operated. Furthermore, a user needs to exert great force to the flat display to overcome the friction force created between the mounting bracket 20 and the support member 10.
Therefore, a new elevating mechanism for a flat-panel display monitor is desired to overcome the above-described shortcomings.